ON FOSSIL CHILOSTOMATOUS BRYOZOA FROM AUSTRALIA. 423 



23. Fossil Chilostomatotjs Brtozoa from Muddy Creek, Victoria, 

 <5fc. By Arthur Wm. Waters, Esq., F.G.S. (Bead May 9, 



1883.) 



[Plate XII.] 



The fossils to be described were collected by Mr. J. Bracebridge 

 "Wilson, of Geelong, who obtained them from Muddy Creek, 

 Hamilton ; Bird Eock, near Geelong ; and Waurn Ponds, — all from 

 the formation which has been called in Australia " Miocene." 



As I had already described Australian Bryozoa from beds of the 

 same age, I undertook the examination of these when Mr. W'llson 

 so kindly sent them to me ; and perhaps it would have been better 

 for science if I had not so readily done so, but if a careful observer 

 like Mr. Wilson, who is near the localities, had himself undertaken 

 the description of the collection. 



They were sent to me for description with the request that the 

 collection should afterwards be handed over to the Museum of the 

 Geological Society ; and I am sure I am only expressing the general 

 feeling of the Fellows when I say that the Society is much indebted 

 to Mr. Wilson for presenting them with collections upon which he 

 had already spent much labour. 



Perhaps the most interesting forms are the Catenicellce, sl genus 

 which Mr. Wilson was the first to point out occurred fossil (Journ. 

 Micr. Soc. of Victoria, vol. i. p. 60, 1880), giving descriptions of 

 12 species. Shortly after this I described and figured a few species 

 which I found in the material from Curdies Creek (Quart. Journ. 

 Geol. Soc. vol. xxxvii. p. 309). 



In order to understand the fossil Catenicellce, which are repre- 

 sented by 13 species, it became necessary to examine as many cal- 

 cined and also decalcified species as were available ; and while any 

 examination of merely dried specimens cannot supply the place of 

 the study of living animals, or even of spirit-specimens, yet it 

 has brought out several points which are worthy of further investi- 

 gation. Among others it has shown that as soon as the operculum 

 is removed there is great difficulty in studying the oral aperture, as 

 there is often a notch at the proximal edge, which 

 simulates the sinus of such genera as Schizoporella. Fig. I. 



It also seems that this notch is sometimes replaced 

 by a suboral pore. C. rufa, MacGillivray, fur- 

 nishes a good example of this (fig. 1) ; for we find, upon 

 separating the operculum, that both the distal 

 and proximal edges are curved upwards, thus 

 giving the operculum a crescentic shape, without 

 any indication of the position of the notch. Thus 

 a portion of the aperture is not closed by the 

 operculum; and here, unless I am mistaken in 



the appearance, the aperture must be divided into two parts : 



2h2 



